1. Field of the Invention(s)
The present invention(s) generally relate to power amplification. More particularly, the invention(s) relate to systems and methods for adaptive linearization of power amplification.
2. Description of Related Art
With ever increasing and nearly ubiquitous use of wireless communication services, the demand for backhaul capacity for wireless communication networks is increasing exponentially. A high capacity microwave point-to-point link has low recurring cost and practically no right-of-way issues. Installation can usually be completed in a few weeks once the licensing has been secured. A microwave link essentially consists of a pair of wireless transmitter and receiver, one at each end. One of the most important parameters of such a link is the output power of the transmitter which directly affects the system gain of the link and therefore the size of the antenna that must be used for a given link distance. In a wireless backhaul network, higher output power is almost universally preferred and is only limited by the linear output power that can be obtained from the transmitter while meeting regulatory and power consumption requirements.
An important aspect of microwave radio link design is the efficiency of the power amplifier. Typically, almost 40 to 60% of the total DC budget of a transceiver is consumed by the power amplifier (PA) alone. The efficiency limitation is a result of the requirement that the output power from the PA must be obtained at or below a specified IMD3 level. This is required to both meet the regulatory requirement (such as those specified by FCC in US and ETSI in Europe) and to achieve a specified BER on the receiver side for a given received signal level.